The present invention relates to shielding electronic assemblies, and, more particularly, to a system for RFI/EMI-shielding individual modules of electronic assemblies. The invention has particular application and advantage when used in connection with RFI/EMI shielding of non-repairable, disposable electronic modules and will be described in connection with such use although other uses are contemplated.
It is a common approach in the shielding of electronic assemblies, in order to limit radio frequency interference (RFI) and electromagnetic interference (EMI) created by them or to protect them from RFI/EMI interference, to enclose the parts within a substantially continuous, electrically conductive shell, such as a sheet metal chassis or a conductive film-coated plastic enclosure. Thus, as shown in FIGS. 1-3, an electronics assembly 10 having a plurality of modules 12 therein (wherein perhaps only one module emits RF and/or EM radiation) is entirely housed in a metal shielding enclosure 14 as depicted in FIG. 2 or in a plastic enclosure 16 having a shielding coating 18 on the surface thereof as depicted in FIG. 3.
The disadvantages of the approach of FIG. 2 are mainly complexity and high cost, since a complete chassis-shell, with multiple electrical and mechanical connections along its joints, must be provided inside a mostly appearance/human interface-oriented outer plastic enclosure (not shown). Among the disadvantages of the approach of FIG. 3 is difficulty in cost-effectively providing reliable electrical continuity across plastic enclosure joints. Any discontinuities in those joints, forming over time due to, e.g. plastic warpage, may result in an unacceptable drop in shielding efficiency.